No abstract available.
Adult* ; Anatomic Landmarks* ; Humans ; Vertical Dimension*

INTRODUCTION: Accurate diagnosis and treatment planning are very important for orthognathic surgery. A small error in diagnosis can cause postoperative functional and esthetic problems. Pre-existing 2-dimensional (D) chephalogram analysis has a high likelihood of error due to its intrinsic and extrinsic problems. A cephalogram can also be inaccurate due to the limited anatomic points, superimposition of the image, and the considerable time and effort required. Recently, an improvement in technology and popularization of computed tomography (CT) provides patients with 3-D computer based cephalometric analysis, which complements traditional analysis in many ways. However, the results are affected by the experience and the subject of the investigator. MATERIALS AND METHODS: The effects of the sources human error in 2-D cephalogram analysis and 3-D computerized tomography cephalometric analysis were compared using Simplant CMF program. From 2008 Jan to 2009 June, patients who had undergone CT, cephalo AP, lat were investigated. RESULTS: 1. In the 3 D and 2 D images, 10 out of 93 variables (10.4%) and 11 out 44 variables (25%), respectively, showed a significant difference. 2. Landmarks that showed a significant difference in the 2 D image were the points frequently superimposed anatomically. 3. Go Po Orb landmarks, which showed a significant difference in the 3 D images, were found to be the artificial points for analysis in the 2 D image, and in the current definition, these points cannot be used for reproducibility in the 3 D image. CONCLUSION: Generally, 3-D CT images provide more precise identification of the traditional cephalometric landmark. Greater variability of certain landmarks in the mediolateral direction is probably related to the inadequate definition of the landmarks in the third dimension.
Anatomic Landmarks ; Complement System Proteins ; Humans ; Orthognathic Surgery ; Research Personnel

PURPOSE: The aim this study was to compare the accuracy of orthodontists and dentomaxillofacial radiologists in identifying 17 commonly used cephalometric landmarks, and to determine the extent of variability associated with each of those landmarks. MATERIALS AND METHODS: Twenty digital lateral cephalometric radiographs were evaluated by two groups of dental specialists, and 17 cephalometric landmarks were identified. The x and y coordinates of each landmark were recorded. The mean value for each landmark was considered the best estimate and used as the standard. Variation in measurements of the distance between landmarks and measurements of the angles associated with certain landmarks was also assessed by a subset of two observers, and intraobserver and interobserver agreement were evaluated. RESULTS: Intraclass correlation coefficients were excellent for intraobserver agreement, but only good for interobserver agreement. The least reliable landmark for orthodontists was the gnathion (Gn) point (standard deviation [SD], 5.92 mm), while the orbitale (Or) was the least reliable landmark (SD, 4.41 mm) for dentomaxillofacial radiologists. Furthermore, the condylion (Co)-Gn plane was the least consistent (SD, 4.43 mm). CONCLUSION: We established that some landmarks were not as reproducible as others, both horizontally and vertically. The most consistently identified landmark in both groups was the lower incisor border, while the least reliable points were Co, Gn, Or, and the anterior nasal spine. Overall, a lower level of reproducibility in the identification of cephalometric landmarks was observed among orthodontists.
Anatomic Landmarks ; Cephalometry ; Incisor ; Orthodontics ; Reproducibility of Results ; Specialization ; Spine

Lumbar spine fusion has become a widely accepted surgery for the management of spinal disorders. However, one of the disadvantages of conventional surgery is the extensive soft tissue dissection that is necessary in order to expose the anatomic landmarks for screw insertion and the fusion bed. The tissue injury that occurs during the surgical approach can result in increased postoperative morbidity, pain, infection and impaired spinal function. Therefore, the goals of the minimally invasive spinal fusion procedure are to minimize tissue injury. The application of percutaneous lumbar pedicle fixation techniques to the lumbar spinal diseases is theoretically sound. However, the indication and technology are currently in evolution. Although the percutaneous pedicle screw fixation technique has a logical basis and is appealing to the patient and surgeon alike, long-term studies will clearly determine their advantages compared with conventional open surgeries
Anatomic Landmarks ; Humans ; Logic ; Spinal Diseases ; Spinal Fusion ; Spine

OBJECTIVE: Determining the location of paraclinoid aneurysms for microsurgery is important for selecting treatment options, especially when deciding on the release of the dural ring in direct clipping. We examined the reliability of using the optic strut as an anatomical landmark for evaluating the location of paraclinoid aneurysms. METHODS: Cadaveric dissection was performed to establish the relationship of the optic strut to the dural ring. Results from these anatomic studies were compared with the three-demensional computed tomographic angiographic (3D-CTA) findings of nine patients with ten paraclinoid aneurysms between May 2004 and October 2005. These, 3D-CTA results were then compared with intraoperative findings. RESULTS: The inferior boundary of the optic strut accurately localized the point at the proximal dural ring in cadaveric study. The optic strut and its relationship to the aneurysms was well observed on the multiplanar reformats of 3D-CTA. During microsurgery, nine of ten aneurysms were verified to arise from distal to the upper surface of the optic strut. Two aneurysms that had arisen between the inferior and superior boundary of the optic strut were observed to lie within the carotid cave. One aneurysm which had arisen at the inferior boundary of the optic strut and directed inferiorly was observed to lie within the cavernous sinus just after the release of the proximal ring. CONCLUSION: The optic strut, as identified with multiplanar reformats of 3D-CTA, provided a reliable anatomic landmark for the proximal rings and an important information about the location of aneurysms around the anterior clinoid process (ACP). Therefore, 3D-CTA and the optic strut could become an invaluable tool and a landmark in the assessment of the location of paraclinoid aneurysms for microsurgery.
Anatomic Landmarks ; Aneurysm* ; Angiography* ; Cadaver ; Cavernous Sinus ; Humans ; Microsurgery*

OBJECTIVE: To identify the volumes of contrast material needed to reach the specific landmarks and contrast pattern during Kambin's triangle approach (KB-A) in lumbar spinal stenosis. METHOD: Sixty patients undergoing KB-A were investigated. Fifty-six patients were included in this study. KB-A were performed with the use of contrast-enhanced fluoroscopic visualization. After confirming the appropriate spinal needle position, a slow injection of up to 5.0 ml of nonionic contrast material was carried out. Under intermittent fluoroscopic guidance, contrast volumes were recorded as flow reached specific anatomic landmarks: ipsilateral inferior or superior neural foramen. RESULTS: After 2.0 ml of contrast was injected, 93.2% of KB-A cases spread to the medial aspect of the inferior pedicle of the corresponding level of injection and 86.3% of KB-A spread to the medial aspect of the superior pedicle of the corresponding level of injection. After 3 ml of contrast was injected, 95.3% of KB-A spread to cover both the medial aspect of the inferior pedicle and the superior pedicle of the corresponding level of injection. A volume of 2 ml of injectate reaches the anterior epidural space 100% of the time. CONCLUSION: This study demonstrates injectate volumes needed to reach the specific anatomic landmarks in KB-A. A volume of 3.0 ml of injectate reaches both the medial aspect of theinferior pedicle and the superior pedicle 94.6% of the time. Therefore, Interventionalists may consider a 1-level instead of a 2-level injection for patients with a bleeding risk or for 2 level central pathology.
Anatomic Landmarks ; Epidural Space ; Hemorrhage ; Humans ; Needles ; Spinal Stenosis

A rigid spino-pelvic fixation to anchor long constructs is crucial to maintain the stability of long fusion in spinal deformity surgery. Besides obtaining immediate stability and proper biomechanical strength of constructs, the S2 alar-iliac (S2AI) screws have some more advantages. Four Korean fresh-frozen human cadavers were procured. Free hand S2AI screw placement is performed using anatomic landmarks. The starting point of the S2AI screw is located at the midpoint between the S1 and S2 foramen and 2 mm medial to the lateral sacral crest. Gearshift was advanced from the desired starting point toward the sacro-iliac joint directing approximately 20degrees angulation caudally in sagittal plane and 30degrees angulation horizontally in the coronal plane connecting the posterior superior iliac spine (PSIS). We made a S2AI screw trajectory through the cancellous channel using the gearshift. We measured caudal angle in the sagittal plane and horizontal angle in the coronal plane. A total of eight S2AI screws were inserted in four cadavers. All screws inserted into the iliac crest were evaluated by C-arm and naked eye examination by two spine surgeons. Among 8 S2AI screws, all screws were accurately placed (100%). The average caudal angle in the sagittal plane was 17.3+/-5.4degrees. The average horizontal angle in the coronal plane connecting the PSIS was 32.0+/-1.8degrees. The placement of S2AI screws using the free hand technique without any radiographic guidance appears to an acceptable method of insertion without more radiation or time consuming.
Anatomic Landmarks ; Cadaver ; Congenital Abnormalities ; Hand* ; Humans ; Joints ; Spine

BACKGROUND AND OBJECTIVES: Sphenoid sinus is surrounded by several important structures and this can make sphenoid sinus surgeries difficult. The aim of this study was to clarify the anatomical features of the sphenoid sinus with its surrounding structures based on 3-dimensional multidetector computed tomography. SUBJECTS AND METHOD: We obtained the sagittal reconstruction images of the sphenoid sinus from of 110 participants and measured various distances in the sphenoid sinus. In addition, we analyzed the impact of anatomical variation on the results of measured distances, such as presence of Onodi cell (Onodi type vs. non-Onodi type) and the location of sphenoid ostium corresponding to the level of sella floor (superior type vs. inferior type). RESULTS: In the Onodi type, the mean distance from the sphenoid ostium to the roof of sphenoid sinus (5.81+/-1.12 mm vs. 10.31+/-2.90 mm, p=0.001) and the mean length of sphenoid sinus roof (4.52+/-1.00 mm vs. 9.89+/-4.17 mm, p=0.001) were significantly shorter than those in the non-Onodi type. In superior type, the mean distance from the sphenoid ostium to the floor of sphenoid sinus (12.44+/-2.63 mm vs. 9.90+/-2.31 mm, p<0.001) and that from sphenoid ostium to the posterior wall of sphenoid sinus (13.44+/-3.27 mm vs. 20.38+/-7.63 mm, p<0.001) were significantly longer compared with those in the inferior type. However, the mean distance from the sphenoid ostium to the roof of sphenoid sinus was shorter (7.49+/-1.86 mm vs. 10.51+/-3.03 mm, p<0.001). CONCLUSION: The present study provides anatomical information about sphenoid sinus with important surgical distance measured between the sphenoid ostium and the surrounding structures, which is essential to avoid the complications during sphenoid surgery.
Anatomic Landmarks ; Floors and Floorcoverings ; Multidetector Computed Tomography ; Sphenoid Sinus

PURPOSE: This study identifies the optimal incision site by describing the relationship between McBurney's point and the base of appendix using the coronal view of abdominal multi-detector computed tomography (MDCT) in patients with acute appendicitis. METHODS: We reviewed the records of 206 patients with positive MDCT findings who were histologically diagnosed with acute appendicitis after appendectomy between January 2014 and September 2015. The outer 1/3 point between two points, the umbilicus and the right anterior superior iliac spine, was marked as McBurney's point on the coronal view. The superoinferior, mediolateral and radial distances between the base of appendix and McBurney's point were measured and recorded. RESULTS: The average age was 35.1±20.3 years. There were 34 patients below the age of 15-years-old (children), and 172 patients over 15-years-old (adults). In 35.4% of patients, the base of appendix was located within a radius of 2 cm from the McBurney's point, in 39.8% it was within 2~4 cm, and in 24.8% was over 4 cm. The average center coordinate of the base of inflamed appendix in our patients is 9.32 mm, 8.31 mm and the distance between two points is 12.5 mm. CONCLUSION: The location of appendix has wide individual variability; therefore the McBurney's point has limitations as an anatomic landmark. If we choose to customize appendectomy incisions considering the base of appendix by using an abdominal MDCT coronal view, additional incision site extension can be reduced.
Anatomic Landmarks ; Appendectomy ; Appendicitis* ; Appendix ; Humans ; Radius ; Spine ; Umbilicus

OBJECTIVE: To compare the observer preference of image quality and radiation dose between non-grid, grid-like, and grid images. MATERIALS AND METHODS: Each of the 38 patients underwent bedside chest radiography with and without a grid. A grid-like image was generated from a non-grid image using SimGrid software (Samsung Electronics Co. Ltd.) employing deep-learning-based scatter correction technology. Two readers recorded the preference for 10 anatomic landmarks and the overall appearance on a five-point scale for a pair of non-grid and grid-like images, and a pair of grid-like and grid images, respectively, which were randomly presented. The dose area product (DAP) was also recorded. Wilcoxon's rank sum test was used to assess the significance of preference. RESULTS: Both readers preferred grid-like images to non-grid images significantly (p < 0.001); with a significant difference in terms of the preference for grid images to grid-like images (p = 0.317, 0.034, respectively). In terms of anatomic landmarks, both readers preferred grid-like images to non-grid images (p < 0.05). No significant differences existed between grid-like and grid images except for the preference for grid images in proximal airways by two readers, and in retrocardiac lung and thoracic spine by one reader. The median DAP were 1.48 (range, 1.37–2.17) dGy*cm2 in grid images and 1.22 (range, 1.11–1.78) dGy*cm2 in grid-like images with a significant difference (p < 0.001). CONCLUSION: The SimGrid software significantly improved the image quality of non-grid images to a level comparable to that of grid images with a relatively lower level of radiation exposure.
Anatomic Landmarks ; Humans ; Lung ; Radiation Exposure ; Radiography* ; Spine ; Thorax*